Show IN THE current number of the North American Review Thornus A Edison tells in a short article be succeededVith the electric light it4s cots new thing for Mr Edison succeed with the electrio light and hence the reader h i not disappointed in finding that the article is but a reiteration iteration of the assertions BO widely published last winter and so goner ally ridiculed by scientific men Mr Edion is always about to succeed and when therefore he tells ns that an exhibition is to begin two months hence it naturally provokes a smile In this respect the methods of two inventors were never more strikingly different than those of Edison and Brush Itls saidthe lattornever permits per-mits any preliminary flourish and never allows piece of machinery togo to-go from his hands until it is ready to entirely accomplish the purpose for which it was intended The failure of tho one and the substantial success of the other attest which is the better method Brnshlong ago discarded the incandescent lamp as impracticable and expensive but Edison seems to have clung to it with a tenacity that its merits scarcely seem to warrant The only change that Edison seem to have mado in his lamp is the I substitution of the fibre ofa Japanese plant for tbe horseshoe paper carbon the form being changed from a horseshoe to a loop It is i claimed that the bamboo is more tenacious and will last longer when subject to concussions Now it is a well known fact in science that incandescent in-candescent carbon no matter what the material is that baa been carbonized carbon-ized even in a perfect vacuum such as Edison claims if healed sufficiently to be of any value as a lightproduc ing agent can last but a short time owing to a peculiar disintegration 01 the material the cauee of which has never been satisfactorily determined It seems that Edison in order to make his loops last n reasonable length of time beats them to a low temperature only thus sacrificing their lightproducing power to add to their durability which must after all be very much limited But grantirj that Edisons lamp is all that he claims it to be he is then Imply on the threshold of the solution of the problem for the question of economy in generating the current at Once arises On this point Edison in his article l carefully confines himself to t generalities He announces however how-ever that ho has decided to use dynamo dy-namo instead of magneto machine and ten of these are to be placed at each station instead of 100 magneto machines at first determined With a 120horse power engine Mr Edison < says he will be able to drive 800 lights of 10candle power each oran or-an aggregate illumination of 8000 candles equal to 500 gas jets of the normal standard of 16candle power each His generator is die cribed as a rather poor form of the DemoDs machine aDd Its comparative compara-tive efficiency may be judged when we state that ten dynamo machine of the Brush system will produce alight a-light equal to 180000 candles as against 8000 candles according to Edieoaa claims Edison again only claims his lights to be 10candle power und therefore will find com difficulty in getting people to accept the dim light of a 10candle power lamp for that of a IGcandle power gas jet But those who have examined ex-amined his new lamp claim that it is i I I not even 10candle power for a large amount of light is lost by the loops being flat and therefore giving scarcely any light at the sides Last winter Edison claimed chat he would soon be able to got ten of these lights from 1hora I power but now claims only five and a half It was apparent to thos le who examined his apparatus las winter from the size of the belt used for driving from the rapidity of the revolution of the machine and from the heating of the armatures and field magnets that each machine was absorbingfrom 5 to 7horso power so that with four machines and the sixty lights he obtained he only got in fact three lights per horse power But granting that ho has succeeded getting even six lights per horse power it would require a consumption of csal for every six lights that would make it far leas economical eco-nomical than gas The plant ia i anther an-ther item IbM Mr Edison does not seem to have considered but which offers a grave obstacle to the introduction uction of the system In each block or district of a half mile square he would require a separate plant and like New in a thickly populated city York it would require a large num her of 120horse power engines to supply the light naeded In New York 800 lamps would RO but a very little way There are 1000000 gas burners in New York and it would require 1500000 of Edisons lamp to supplant them This would re quire about 2600 120horsa power engines and 2o000 dynamo ma chloe If the engines cost i000 each complete and that is a low estimate it would coat 10000000 If f the dynamomachines coat 1000 each which is also a low estimate they would aggregate 25000000 The lamps fixtures wires etc would easily absorb 15000000 more The largest item however would bo the land which in New York City w puldjba enormous especially inHhe basil I > of the city This alone fias j bHn e estimated by c competent authority autho-rity at not lets than 50000 000 The interest and allowance fur dcprecia I tion should not ba less than 10 per cent or 10000000 on the aggregate COt of the plan The running expenses won It exceed 10 000000 and superintendence and collection would coat at feast 1000 000 J Ths miscellaneous expanses might be safely counted at 1000000 10 that the aggregate yearly expenses would be fully 22000000 or 15 per annum for each electrio light A 2 per > 1000 the average annual co t per light for gas is 15 or placed on alight a-light giving equality with Edisons electric light 10 If gas in New York City were Bold at 10 per cent profit it could bo delivered in the I holders at 40 cents per 1000 The actual cost to the companies is 80 cents per 1000 Gas if eelliDjin NawYork at less than 2 per ife and the price could be reduced to 1 tier 1000 and large profits stilt made In Cleveland the introduction introduc-tion of the Brush system for lighting streets and stores has brought down gas fo 125 per 1000 and the gas companies continue to pay dividends notwithstanding Coal for gas Ts cheaper in New York than in Cleve land So it will be seen that Mr Edison cannot possibly produce the electric light for competition with gu for household use The present status of the electric light seems to be hat while it may be used successfully for large spaces it cannot be used economically for household illumina ion |